Back in the 1990s, the robot dog was the great promise of the future. Or at least that's how 90s kids remember it. By the second decade of the 21st century we were supposed to be ditching Fido for robot dogs like AIBO, seen above showing off a few tricks in 1999.

But it wasn't just robot dogs that were supposed to be the pets of tomorrow. Today, we're taking a look back at six of the things that were supposed to be our household pets of the future: from all things robot to miniature rhinos.

1) Robot Dogs

In 1939, the Westinghouse robot Elektro dazzled audiences at the New York World's Fair. But Elektro seemed a bit lonely. Sure, he could walk and talk and even smoke, but he needed a pal. So by 1940 he started to appear with mechanical man's best friend: Sparko, the robot dog.

The robot dog was supposed to be the absolute must-have pet of the future. The only problem? Robot dogs like Sparko (pictured above) don't look very cuddly and they historically haven't seemed very "smart." The Jetsons even tackled the issue in their fourth episode, concluding that a robo-dog was just more trouble than it was worth.

Good old Astro, the flesh-and-blood dog of tomorrow, may have been imperfect. But even in the mid-21st century, an old fashioned dog was still better than a robot pooch.

2) Miniature Horses

Back in 1905, Life magazine ran this cartoon of the lapdog-sized horse of the future. The magazine insisted that this was still 1,000 years into the future, but given current technological advances, there's no good reason we couldn't do this today. Aside from the fact that horses are just filthy poop machines. There, I said it. Mini-horses would be gross and this opinion is in no way shaded by my miserable allergy to horses.

3) Genetically Engineered Mini-Rhinos

The 1982 book The Kids' Whole Future Catalog explained that until recently, "it has been possible to cross only species that are very similar. For instance, a mare and a donkey can be crossbred to get a mule, but the reproductive cells of a horse and a dog will not unite."

But soon, that would change. And an entirely new era of weird animal hybrids would bring us the wonder that is the mini-rhino, pictured above. What other bizzaro hybrids would we see? The sky was the limit.

But no man-animal hybrids. At least that's what George Bush promised us back in 2006 — no maninmals, please.

4) Snakes

Today, snakes aren't exactly an average American pet. They're not as common as dogs, cats, or even hamsters. But they do beat out ferrets and gerbils.

Back in the late 19th century, some people insisted that the snake was the pet of the future. Even if they had to be arrested to make sure that could happen.

The August 22, 1872 edition of the Fort Wayne Daily Sentinel in Indiana:

Dogs have nearly had their day, and so have cats. The household pets of the future will be snakes. To be sure, their introduction will meet with opposition, but prejudice will soon wear away. A Mr. Mann, an English music teacher, has been arrested for keeping snakes loose about his house, and allowing them to crawl into the domiciles of his neighbors. Upon the trial it was shown that Mr. Mann's two little children play with and fondle a young Brazilian boa, and Mr. Mann himself asserted that "these creatures are becoming sought after as pets by many private persons, so that it is difficult to buy one at all now."' The spectacle of a Fifth Avenue belle sweeping down Broadway, leading a pet snake by a silk cord fastened to a silver-plated collar, will be the next sensation.

Image: A tiger snake being handled by the head keeper of Bronx Zoo reptile house in 1922 via Getty

5) Dinosaurs

What kid doesn't want a real-life dinosaur to play with? I know I did. But short of Jurassic Park becoming real, the kids of the 21st century will have to settle for the same robot dinosaur technology that amazed visitors to the 1964 New York World's Fair. Well, not the same technology. But dinosaurs that are much closer to a robot than some real-life Littlefoot.

6) No Animals

And finally, many predicted that the pet of the future was having no pet at all. In fact, some thought we'd have no animals at all. For people of the beforetimes™ who may have seen animals only as a source of profit, this view made sense. Once the machines take over, why would we need beasts of burden?

The horse especially was singled out as set for extinction. Who needed horses in the world when the slick new automobile got everybody where they needed to go without all the horsey waste? Above, we see a French postcard from circa 1900-1910 that predicted the horse would be a mere curiosity by the year 2000.